PQ60033SMX15 Datasheet, PDF (13/15 Pages) SynQor Worldwide Headquarters – Output current limit and short circuit protection

Technical
Specification
PQ60033SMx15
APPLICATION CONSIDERATIONS
Input System Instability: This condition can occur because
any dc-dc converter appears incrementally as a negative
resistance load. A detailed application note titled “Input
System Instability” is available on the SynQor website which
provides an understanding of why this instability arises, and
shows the preferred solution for correcting it.
Application Circuits: Figure D provides a typical circuit
diagram which details the input filtering and voltage trimming.
Vin(+)
Vout(+)
Electrolytic
Vsense(+)
External
Capacitor
R
trim-up
Vin
Input
ON/OFF
Trim
or
Filter
Vsense(^_)
R
trim-down
C_load
I
load
Vin(^_)
Vout(^_)
Figure D: Typical application circuit (negative logic unit, permanently enabled).
Input Filtering and External Capacitance: Figure E provides
a diagram showing the internal input filter components. This
filter dramatically reduces input terminal ripple current, which
otherwise could exceed the rating of an external electrolytic
input capacitor. The recommended external input capacitance
is specified in the Input Characteristics section on the Electrical
Characteristics page. More detailed information is available in
the application note titled “EMI Characteristics” on the SynQor
website.
L
Vin(+)
C
Startup Inhibit Period: The Startup Inhibit Period ensures that
the converter will remain off for approximately 200 ms when it is
shut down for any reason. When an output short is present, this
generates a 5 Hz “hiccup mode,” which prevents the converter
from overheating. In all, there are six ways that the converter
can be shut down, initiating a Startup Inhibit Period:
• Input Under-Voltage Lockout
• Output Over-Voltage Protection
• Over Temperature Shutdown
• Current Limit
• Short Circuit Protection
• Turned off by the ON/OFF input
Vin(^_)
Figure E: Internal Input Filter Diagram (component values
listed on the specifications page).
Product # PQ60033SMx15
Phone [phone]
www.synqor.com
Doc.# 005-0005163 Rev. C
06/28/11
Page 13